micropenis

Bosma Arhinia Microphthalmia Syndrome

Clinical Characteristics
Ocular Features: 

Microphthalmia or clinical anophthalmia are usually present.  Iris colobomas are frequent features.  Occluded or absent nasolacrimal ducts have been reported.

Systemic Features: 

Arhina with anosmia is the most striking feature but it is usually accompanied by midface hypoplasia, a highly arched (or cleft) palate, and preauricular pits.  The nasal bones along with the cribriform plate, and other septal structures may be missing.  Maxillary and paranasal sinuses, together with the olfactory bulbs are often absent.  Intelligence is usually normal.

Choanal atresia is often present.  Hypogonadotropic hypogonadism with micropenis and cryptorchidism is an important feature in males.  Females may experience pubertal delay with menarche anomalies.  

Genetics

Heterozygous mutations in the SMCHD1 gene (18p11) are responsible for this disorder.  There is considerable clinical heterogeneity with many carriers having only minor manifestations.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment for the general disorder has been described.

References
Article Title: 

De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development

Gordon CT, Xue S, Yigit G, Filali H, Chen K, Rosin N, Yoshiura KI, Oufadem M, Beck TJ, McGowan R, Magee AC, Altmuller J, Dion C, Thiele H, Gurzau AD, Nurnberg P, Meschede D, Muhlbauer W, Okamoto N, Varghese V, Irving R, Sigaudy S, Williams D, Ahmed SF, Bonnard C, Kong MK, Ratbi I, Fejjal N, Fikri M, Elalaoui SC, Reigstad H, Bole-Feysot C, Nitschke P, Ragge N, Levy N, Tuncbilek G, Teo AS, Cunningham ML, Sefiani A, Kayserili H, Murphy JM, Chatdokmaiprai C, Hillmer AM, Wattanasirichaigoon D, Lyonnet S, Magdinier F, Javed A, Blewitt ME, Amiel J, Wollnik B, Reversade B. De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development. Nat Genet. 2017 Feb;49(2):249-255.

PubMed ID: 
28067911

Gracile Bone Dysplasia

Clinical Characteristics
Ocular Features: 

The eyes have been described as small.  Aniridia may be present.

Systemic Features: 

This is a usually fatal form of skeletal dysplasia with splenic and ocular features as well.  In utero death is not uncommon while newborns may not survive the neonatal period.  The face has been described as dysmorphic with a high forehead, flat nasal bridge, a cloverleaf-shaped skull, and hypoplastic cranial bones with premature suture closure.  The long bones are dysplastic as well with thinned diaphyses (sometimes fractured in utero), growth plate disorganization, excessive remodeling, and signs of arrested growth.  The ribs share in the dysplasia but pulmonary hypoplasia has also been described.  Most individuals have short limbs.

The spleen can be hypoplastic or aplastic and ascites has been noted in several infants.  Failure to thrive is common and seizures have been reported.  Males may have micropenis and hypospadias while females have been described with labial fusion.  

Low parathyroid hormone levels and hypocalcemia has been reported in most individuals.

Genetics

Heterozygous mutations in the FAM111A gene (11q12.1) have been associated with this disorder.  The functional role of FAM111A products is unknown but likely play a role in calcium metabolism, parathyroid hormone secretion, and osseous development.

Mutations in the same gene can be responsible for the allelic autosomal dominant Kenny-Caffey syndrome (127000) with some similar features.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

FAM111A mutations result in hypoparathyroidism and impaired skeletal development

Unger S, Gorna MW, Le Bechec A, Do Vale-Pereira S, Bedeschi MF, Geiberger S, Grigelioniene G, Horemuzova E, Lalatta F, Lausch E, Magnani C, Nampoothiri S, Nishimura G, Petrella D, Rojas-Ringeling F, Utsunomiya A, Zabel B, Pradervand S, Harshman K, Campos-Xavier B, Bonafe L, Superti-Furga G, Stevenson B, Superti-Furga A. FAM111A mutations result in hypoparathyroidism and impaired skeletal development. Am J Hum Genet. 2013 Jun 6;92(6):990-5.

PubMed ID: 
23684011

Baraitser-Winter Syndrome 1

Clinical Characteristics
Ocular Features: 

Ptosis (both unilateral and bilateral), hypertelorism, prominent epicanthal folds, and colobomata are common.  The iris stroma may be dysplastic and correctopia has been observed.  Visual acuity has not been measured.

Systemic Features: 

Postnatal growth retardation leads to short stature.  Microcephaly and morphological aberrations in the brain such as lissencephaly, agenesis of the corpus callosum and pachygyria are present.  Seizures and developmental delays are common.  Hearing loss is sensorineural in type.

The ears are low-set and the posterior hair line may be low as well.  The nasal bridge appears broad and the nose appears short. Male genitalia are often underdeveloped.  Bicuspid aortic valves, patent ductus arteriosus, and aortic stenosis have been reported.

Genetics

Heterozygous mutations in the ACTB gene (7p22.1) are responsible for this apparent autosomal dominant syndrome.  However, all patients have been sporadic.

This condition is clinically similar to Baraitser-Winter syndrome 2 (614583) which is a unique entity caused by a mutation in ACTG1. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No specific treatment is available.

References
Article Title: 

New ocular finding in Baraitser-Winter syndrome

Rall N, Leon A, Gomez R, Daroca J, Lacassie Y. New ocular finding in Baraitser-Winter syndrome. Eur J Med Genet. 2017 Oct 9. pii: S1769-7212(17)30156-8. doi: 10.1016/j.ejmg.2017.10.006. [Epub ahead of print].

PubMed ID: 
29024830

Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases

Verloes A, Di Donato N, Masliah-Planchon J, Jongmans M, Abdul-Raman OA, Albrecht B, Allanson J, Brunner H, Bertola D, Chassaing N, David A, Devriendt K, Eftekhari P, Drouin-Garraud V, Faravelli F, Faivre L, Giuliano F, Guion Almeida L, Juncos J, Kempers M, Eker HK, Lacombe D, Lin A, Mancini G, Melis D, Lourenco CM, Siu VM, Morin G, Nezarati M, Nowaczyk MJ, Ramer JC, Osimani S, Philip N, Pierpont ME, Procaccio V, Roseli ZS, Rossi M, Rusu C, Sznajer Y, Templin L, Uliana V, Klaus M, Van Bon B, Van Ravenswaaij C, Wainer B, Fry AE, Rump A, Hoischen A, Drunat S, Riviere JB, Dobyns WB, Pilz DT. Baraitser-Winter cerebrofrontofacial syndrome: delineation of the spectrum in 42 cases. Eur J Hum Genet. 2014 Jul 23.

PubMed ID: 
25052316

De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome

Riviere JB, van Bon BW, Hoischen A, Kholmanskikh SS, O'Roak BJ, Gilissen C, Gijsen S, Sullivan CT, Christian SL, Abdul-Rahman OA, Atkin JF, Chassaing N, Drouin-Garraud V, Fry AE, Fryns JP, Gripp KW, Kempers M, Kleefstra T, Mancini GM, Nowaczyk MJ, van Ravenswaaij-Arts CM, Roscioli T, Marble M, Rosenfeld JA, Siu VM, de Vries BB, Shendure J, Verloes A, Veltman JA, Brunner HG, Ross ME, Pilz DT, Dobyns WB. De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome. Nat Genet. 2012 Feb 26;44(4):440-4.

PubMed ID: 
22366783

Trichomegaly Plus Syndrome

Clinical Characteristics
Ocular Features: 

Eyelashes are described as ‘long’, and the eyebrows are bushy.  The majority of individuals have poor vision secondary to severe receptor dysfunction.  Night blindness and severe photophobia are features in some cases.  Both retinal and choroidal atrophy have been diagnosed in the first 5 years of life and most patients have a progressive and extensive pigmentary retinopathy.

Systemic Features: 

Scalp alopecia and sparse body hair is common in spite of the trichomegaly of the eyebrows and eyelashes.  Frontal bossing has been noted in some patients.  Pituitary dysfunction is suggested by low growth hormone levels, features of hypogonadotropic hypogonadism, and possibly hypothyroidism.

Some deficit of cognitive function is usually present and a few patients have been described as mentally retarded.  There is evidence of progressive neurological damage both centrally and peripherally. Developmental milestones are often achieved late and some individuals have been observed to regress during the first decade of life.  The peripheral neuropathy includes both sensory and motor components.  Sensory nerve action potentials may be lost in the first decade while early motor functions may regress during the same period.  Several patients have had evidence of progressive cerebellar ataxia.

Genetics

Compund heterozygous mutations in PNPLA6 (19p13.2), coding for neuropathy target esterase, have been found in several patients presumed to have this condition.  Autosomal recessive inheritance has been proposed on the basis of a single family in which an affected brother and sister were born to first cousin parents.   

The relationship of this disorder to that found in two cousins, offspring of consanguineous matings, described as ‘cone-rod congenital amaurosis associated with congenital hypertrichosis: an autosomal recessive condition’ (204110 ) is unknown.  They were described as having visual impairment from birth and profound photophobia.  Fundus changes were minimal with a bull’s eye pattern of pigment changes in the macula described as indicative of a rod-cone congenital amaurosis.  ERG responses were unrecordable.  These individuals apparently did not have other somatic, psychomotor or neurologic deficits.

Mutations in PNPLA6 occur in other conditions including a form of Bardet-Biedl Syndrome (209900), and Boucher-Neuhauser Syndrome (215470) also known as Chorioretinopathy, Ataxia, Hypogonadism Syndrome in this database.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for this condition although growth hormone and testosterone supplementation have been reported to have the appropriate selective effects.

References
Article Title: 

Neuropathy target esterase impairments cause Oliver-McFarlane and Laurence-Moon syndromes

Hufnagel RB, Arno G, Hein ND, Hersheson J, Prasad M, Anderson Y, Krueger LA, Gregory LC, Stoetzel C, Jaworek TJ, Hull S, Li A, Plagnol V, Willen CM, Morgan TM, Prows CA, Hegde RS, Riazuddin S, Grabowski GA, Richardson RJ, Dieterich K, Huang T, Revesz T, Martinez-Barbera JP, Sisk RA, Jefferies C, Houlden H, Dattani MT, Fink JK, Dollfus H, Moore AT, Ahmed ZM. Neuropathy target esterase impairments cause Oliver-McFarlane and Laurence-Moon syndromes. J Med Genet. 2015 Feb;52(2):85-94.

PubMed ID: 
25480986
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